Known latches are used to releasably secure vehicle doors in a closed position. The latch is mounted on the door and includes a retention plate having an opening which receives a striker that is typically mounted on a fixed structure of the vehicle. A latch bolt in the form of a rotatable claw having a mouth is typically pivotably mounted to the retention plate. The claw is provided with fully latched and first safety abutments against which a pawl, also pivotally mounted to the retention plate, may engage. As the door is closed, the striker enters the opening of the retention plate and the mouth of the claw, rotating the claw and engaging the pawl with one of the abutments, thereby releasably retaining the claw and maintaining the door in a closed position. Mechanical or electrical linkages are provided from the latch to handles, buttons and the like to control the operation of the latch.
Latches on different vehicles, and in particular different latches on a particular vehicle, can have different security/operating modes. Thus, a latch may be a) openable by operation of an inside door handle, b) openable by operation of an outside door handle, c) lockable by operation of an inside sill button or the like, d) lockable by operation of an outside key barrel or the like, e) lockable by operation of a remote keyless entry (RKE) device, and f) superlockable by operation of a RKE device or outside key barrel.
The state of a particular latch may include one or more of the following modes: a) unlocked, b) locked (i.e., operation of an outside door handle does not unlatch the latch, but operation of an inside door handle does unlatch the latch), c) superlocked (wherein any number of operations of an inside door handle or an outside door handle, in any order, does not unlatch the latch), and d) child safety on (wherein operation of an inside door handle does not unlatch the latch, but operation of an outside door handle may or may not unlatch the latch, depending upon whether the door is locked or unlocked).
Furthermore, a certain sequence of events can be used to perform desired functions. With a locked latched door, operation of an inside door handle may unlatch the latch and, at the same time, unlock the latch. Upon subsequent closing of the door, the door is unlocked and can then be opened by operation of the outside door handle. This is known as override unlocking and prevents vehicle keys from being locked in the vehicle. This mode of operation is also useful to provide for opening of a locked door in the child safety on mode. Even though operation of the inside door handle does not unlatch the latch, it unlocks the latch and a subsequent operation of an outside door handle enables the latch to be unlatched.
A sill button associated with certain types of latches (typically driver door latches) cannot be depressed when the door is open. This also prevents keys from being locked in the vehicle. The only ways of externally locking such a latch are to either close the door and insert a key into a key barrel to lock the latch or to operate a RKE device.
Certain other types of latches require an outside door handle to be lifted when the door is in the open position to enable the sill button to be pushed down to lock the door when the door is subsequently closed. Thus, the driver has to perform a specific sequence of events (i.e., lift the outside door handle and then depress the sill button) to lock the door. This again is aimed at preventing keys from being locked in the vehicle.
There are several modes of operation of known door locks, and the way in which these functions are performed are typically carried out by mechanisms of the door latch, as opposed to mechanisms remote from the door latch. Ultimately, whichever mechanism is used, the door will only open when the pawl is moved out of engagement from the claw. The locking, the superlocking, and the child safety modes all relate to either providing a connection between a door handle or a power actuator (e.g., an electric motor) driven under the influence of a signal received from an RKE device or door handle and the pawl to move the pawl or breaking or blocking the connection to prevent movement of the pawl.
Car door latches are typically mounted at the rear of a car door, and the car door is pivotally mounted at a front edge. Typically, an inside door handle is mounted on the inside of the door and towards the front edge, and therefore a connection needs to be provided to connect the inside door handle with the door latch. Depending on the location of the inside door handle and the nature of the connection with the latch (e.g., in some cases the nature of the connection is simply to provide the unlatching of the door, whereas in other cases the nature of the connection is to provide for unlocking and unlatching of the door), different latches require different types of connections and connection orientations to be able to actuate the door latch.
In doors fitted with a sill button or another visual status indicator to indicate the locked state of a particular latch and the changing of that locked state, superlocking latches can be used to manually manipulate the sill button or the visual status indicator to provide an indication corresponding to the particular latch being unlocked, although the latch in fact remains superlocked. This situation is undesirable since it results in uncertainty in the mind of a vehicle user as to whether the latch remains superlocked, locked or unlocked. In turn, this may result in a user pulling on an inside or outside handle with excessive force to unlatch the latch under the misconception that it is unlocked when it is not, which may cause damage to the latch or associated linkages.
The present invention seeks to overcome or at least mitigate the problems of the prior art.